The present invention relates to coaxial cables and connectors. In particular, the invention relates to a converter or adapter for joining coaxial cables to coaxial connectors, where the connector is not specifically designed to accept the size of the coaxial cable.
All coaxial cable connectors are designed to work with specific cable conductor sizes and types, or specific ranges of cable conductor sizes and types. If a need arises for using a coaxial connector with a coaxial cable which is outside the designed range of the connector, it is typically not possible to accommodate the out-of-range cable. Such needs are becoming increasingly common as the increased performance of larger coaxial cables is desired in high performance applications. Specifically, larger coaxial cables are often desired to reduce signal losses in applications where the signal must be transmitted over an extended distance.
In many situations where use of a larger coaxial cable is desired, system designers often are unable or prefer not to use larger coaxial connectors which are capable of accepting a larger coaxial cable because the interconnect system is already in use in other parts of the system. Instead of being able to use the desired connector and cable combination, a smaller coaxial cable than desired must be used or the connector must be substantially redesigned to accept the desired cable. The use of a smaller than desired coaxial cable or redesigned connector may lead to less than optimal performance of the system in which the connector and cable assembly is used, or, if a certain level of performance is absolutely required, may require completely new connector and/or cable designs to obtain the desired performance. Neither of these options is desirable to the end user, as less than optimal performance may not be acceptable in the intended application, and new connector or cable designs may be exceptionally expensive.
Clearly, it would be highly desirable if an adapter or converter was available to allow the easy and quick combination of coaxial connectors and coaxial cables which where not originally designed for use together, while at the same time maintaining the performance levels of the connector and cable.
The present invention provides a versatile converter for terminating a coaxial connector to a coaxial cable when the cable shield layer outer diameter is larger than an interior dimension of the connector shell. The converter may be used to match the impedance of either the cable or the connector, or may be used to smoothly transition between the impedance of the cable and the impedance of the connector.
In a preferred embodiment, the converter includes a conductive shell having a first cylindrical section and a second cylindrical section. A transitional section tapers between the first and second cylindrical sections. The first cylindrical section has an inner diameter larger than the outer diameter of the cable conductive shield layer, and the second cylindrical section has an outer diameter smaller than the interior dimension of the connector shell. A dielectric insulation insert is positioned with the transitional section of the converter shell. The dielectric insulation insert may be formed so that the converter impedance matches the impedance of either the coaxial cable or the connector, or it may alternately be formed to smoothly transition from the impedance of the cable to the impedance of the connector.
In use, the cable conductive shield layer is electrically connected to the first cylindrical section of the converter and the second end of the converter is electrically connected to the connector outer shell, thereby establishing electrical continuity between the connector shell and the cable shield. The cable inner conductor passing through the converter and into the connector where it is terminated in the normal manner.